In metaphysics, particulars or individuals are usually contrasted with universals. Universals concern features that can be exemplified by various different particulars. Particulars are often seen as concrete, spatiotemporal entities as opposed to abstract entities, such as properties or numbers. There are, however, theories of abstract particulars or tropes. For example, Socrates is a particular. Redness, by contrast, is not a particular, because it is abstract and multiply instantiated . In nominalist view everything is particular. Universals in each moment of time from point of view of an observer is the collection of particulars that participates it.( even a void collection ).
